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Unformatted text preview: 4.2.6 Supernovae in binary systems
It is quite common for a supernova to be in a binary system. In fact, some
supernovae are caused by a companion star's dumping mass on a star, until
the latter explodes (section 4.3.4, below). What happens to the binary system
when the explosion occurs? It turns out that the force of the explosion is not
an important eect on the star, but its mass loss is.
Before the supernova we have (say) two stars in circular orbit:
v1
M1 r1 r2
CoM M2
v2 Putting the CoM at rest, we have M1v1 + M2v2 = 0 M1r1 + M2r2 = 0 : Let M1 be the mass that explodes. Typically it is the more massive star that
explodes, so M1 > M2. When it explodes, it quickly (and spherically, say)
blows o most of its mass, so that its new mass M10 is M10 = M1 M
and we have 87...
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